<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            padding: 0;
            margin: 0;
            list-style-type: none;
        }

        .mainBox {
            width: 800px;
            height: 100vh;
            margin: 0 auto;
        }

        a {
            text-decoration: none;
        }

        .red1 {
            background-color: rebeccapurple;
            width: 100px;
            height: 100px;
        }
        .red1:hover{
            background-color: #ff9bf9;
        }
    </style>
</head>

<body>
    <div class="mainBox">
        <div class="red1"></div>
    </div>
</body>

</html>